In the manufacture of tissue products such as facial tissue, bath tissue, and paper toweling, softness is imparted to the product by adhering the web to a rotating creping cylinder and thereafter dislodging it from the creping cylinder with a doctor blade. In order for the creping process to be effective, it is necessary to obtain proper adhesion between the web and the creping cylinder, which is generally achieved by the addition of a creping adhesive. Very small amounts of adhesive are applied per revolution of the creping cylinder. For good creping, an adhesive coating must build up on the surface of the dryer and is continuously renewed during each revolution of the dryer as a small amount is removed by the doctor blade and replaced by freshly applied adhesive. The newly applied adhesive is incorporated into the existing coating, which is reactivated by taking on moisture from the fresh application. Therefore, rewettability is an important property of a good creping adhesive.
In an effort to seek new and improved creping adhesives, a water-soluble, thermosetting, cationic polyamide resin creping adhesive was developed as described in U.S. Pat. No. 4,501,640 to Soerens. However, although such a creping adhesive exhibits good adhesion, the thermosetting nature of such adhesives works against rewettability because after cross-linking (curing) the addition of moisture is no longer able to soften and conform the coating sufficiently to optimally bond with the tissue web at the pressure roll nip.
Therefore there is a need for an improved method of creping cellulosic webs which uses a creping adhesive exhibiting improved wettability.